Generation Biodiesel Research Articles

Exploring indigenous freshwater chlorophytes in integrated biophotovoltaic system for simultaneous wastewater treatment, heavy metal biosorption, CO2 biofixation and biodiesel generation

The study explored the combined photosynthetic activities of two green microalgal species, Tetradesmus obliquus and Tetradesmus reginae, on an integrated biophotovoltaic (BPV) platform for simultaneous wastewater treatment, toxic metal biosorption, carbon biofixation, bioelectricity generation and biodiesel production. The experimental setup comprised of a dual-chambered BPV with copper anode surrounded by T. obliquus in BG11 media, and copper cathode with T. reginae in municipal wastewater separated by Nafion 117 membrane. The study reported a maximum power density of 0.344 Wm−2 at a cell potential of 0.415 V with external resistance of 1000 Ω and 0.3268 V maximum open-circuit voltage. The wastewater electrical conductivity and pH increased from 583 ± 22 to 2035 ± 29.31 mS/cm and 7.403 ± 0.174 to 8.263 ± 0.055 respectively, signifying increased photosynthetic and electrochemical activities. Residual nitrogen, phosphorus, chemical oxygen demand, arsenic, cadmium, chromium and lead removal efficiencies by T. reginae were 100%, 80.68%, 71.91%, 47.6%, 88.82%, 71.24% and 92.96%, respectively. T. reginae accumulated maximum biomass of 0.605 ± 0.033 g/L with a CO2 biosequestration rate of 0.166 ± 0.010 gCO2/L/day and 42.40 ± 1.166% lipid content. Methyl palmitate, methyl undecanoate and 13-octadecenoic acid with relative abundances of 37.24%, 24.80% and 12.02%, respectively were confirmed.

Ultrasound-assisted biodiesel generation from waste edible oil using CoFe2O4@GO as a superior and reclaimable nanocatalyst: Optimization of two-step transesterification by RSM

In current study, CoFe2O4@graphene oxide (GO) and CoFe2O4 heterogeneous nanocatalysts were successfully synthesized using the ultrasonic method and then used to generate biodiesel from waste edible oil (WEO) in a two-step transesterification process. To do so, the catalysts surface was characterized using CO2-TPD, SEM, EDX/Map, XRD, VSM, BET, FTIR, and DLS analyses. Also, central composite design (CCD) was utilized to optimize the impact of various factors on biodiesel generation. With the help of ultrasonication, the highest biodiesel yield using CoFe2O4 (91.64%) and CoFe2O4@GO (98.17%) was achieved at time of 55.75 min, temperature of 64.75 °C, methanol/oil ratio of 16.05:1 and catalyst concentration of 5.22 wt%. Also, the highest biodiesel yield without ultrasonication using CoFe2O4 and CoFe2O4@GO were gained as 58.96 and 67.13%, respectively. Moreover, the highest predicted biodiesel yield in the presence of CoFe2O4@GO by the RSM-CCD method is 98.95%, which is the maximum biodiesel yield ever achieved from WEO. The outcomes show that ultrasound-assisted transesterification is an efficient method for biodiesel generation, which can reduce costs and production time. After 5 reuse cycles, the CoFe2O4@GO nanocatalyst showed a yield of about 90%, which is due to its desirable magnetic attributes and easy separation. According to international standards and using FT-IR and HNMR analyses, the biodiesel produced can be used in diesel engines without further modification. Besides, kinetic and thermodynamics studies indicated that the generation reaction of biodiesel using both nanocatalysts is endothermic and non-spontaneous.

Observer-based virtual sensors for microalgae cultures monitoring

In this paper, a nonlinear observer design is presented for simultaneous parameter estimation and state variables estimation. The case of study is microalgae cultures for biodiesel generation, where reaction rates, biomass concentration, intracellular quota and nitrogen concentration are critical variables that provide information about the state of the process. However, these variables might be difficult to measure due to the lack of specific instruments, high sensor costs or infeasibility of installation in the process. Therefore, two observer-based virtual sensors are presented in this paper as an analytical alternative to perform estimation of the main important variables or parameters of the process: a nonlinear adaptive observer and a nonlinear high-gain observer. The observers are based on the Droop´s mathematical model that describes the ability of microalgae to store nutrients and the decoupling between substrate uptake and biomass growth. Numerical simulations are made in order to evaluate the performance of the proposed observers.

A hydrodynamic cavitation-assisted system for optimization of biodiesel production from green microalgae oil using a genetic algorithm and response surface methodology approach.

In the present research work, the effect of operating parameters such as molar ratio (3:1-7:1), catalyst concentration (0.5-1.5%), reaction time (5-25min), and operating pressure (0-4bar) on the rate of biodiesel conversion percentage for the transesterification reaction using hydrodynamic cavitation (HC) has been studied. Response surface methodology (RSM) and genetic algorithms (GA) were used to find the best condition. The best conditions for biodiesel generation were a molar ratio of 6.5:1, a catalyst concentration of 1.301 wt.%, a reaction period of 11.5min, and operating pressure of 3.6bar. The maximum yield of biodiesel obtained under optimal conditions was 97.3%. The reaction time for biodiesel produced by HC under similar conditions as the conventional technique was reduced by 85%. The HC approach is preferable to the conventional method due to its shorter processing time.

EFFECTS OF SALTS IN BIODIESEL DERIVED CRUDE GLYCEROL ON VANCOMYCIN PRODUCTION FROM AMYCOLATOPSIS ORIENTALIS ATCC® 19795™

Bioconversion of crude glycerol (CG), the primary byproduct in biodiesel generation, is currently of great interest due to its promising potential in producing chemicals of high commercial interest. The efficient use of CG is still limited primarily due to the presence of impurities that may vary in composition based on the parent feedstock, biodiesel generation process, and any recovery/ purification conducted. In this study, laboratory scale fermentation of vancomycin using Amycolatopsis orientalis ATCC® 19795™ was analyzed based on the presence of salts as an impurity in biodiesel derived CG. Results showed that CG as the sole carbon source inhibited the cell growth, but the vancomycin production was approximately the same (158±2 mg L-1) as that of refined glycerol (RG)-based media at varying initial glycerol concentrations studied (5 g L-1 to 40 g L-1). NaCl as an impurity in biodiesel derived CG reduced both the growth yield coefficient (YX/S) and vancomycin formation at high concentrations. Among other salts tested are NaNO3 and KCl. NaNO3 (0.8 g L-1) supplemented media generated a higher YX/S (1.1 g biomass (g glycerol consumed)-1) and a similar vancomycin concentration (193 mg L-1) compared to the media with added NaCl (YX/S of 0.4 g biomass (g glycerol consumed)-1 and a vancomycin concentration of (190 mg L-1)). Relatively, both the YX/S (0.55 g biomass (g glycerol consumed)-1) and vancomycin concentration (135 mg L-1) was reduced in KCl (0.7 g L-1) supplemented media. The results suggest the potential of using CG (with salts i.e., NaCl as impurities) as an excellent low-cost alternative for RG in fermentation of vancomycin using Amycolatopsis orientalis ATCC® 19795™.

Experimental Investigation of Engine Performance for 2nd Generation Biodiesel Derived from Mg2Zr5O12 Catalyst

In the present study, experimental analyses were conducted by using biodiesel derived from second-generation feedstock. In terms of cost and accessibility, second-generation feedstock has gained more attention due to its environmental approach. Waste-cooking-oil-derived methyl ester was produced through a transesterification reaction in the presence of a synthesized magnesium zirconate (Mg2Zr5O12) heterogeneous catalyst. This trans-esterified waste cooking oil (WCO) was used as biodiesel and was blended with diesel in 10%, 20%, 30%, 40%, and 50% by volume ratio for further analysis. The fuel properties of pure and blended biodiesel were investigated in terms of flash point, density, kinematic viscosity, and lower heating value as per the American Society for Testing and Materials (ASTM) D-6751 standards. For each blended fuel, the engine performance and gaseous emissions trend with engine loads of 0, 3, 6, 9, and 12 kg were measured on a Kirloskar TV1 IC engine. The results indicated that the 40% blended biodiesel has the maximum brake thermal efficiency (BTE) of 19.13% and exhaust gas temperature (EGT) of 6.98% increment, also showing an increase with respect to engine load. On the other hand, brake-specific fuel consumption (BSFC) was highest for 40% blending as 36.48% increase, and that decreases with the increase in engine loads. Significant reductions in carbon monoxide (CO) and unburned hydrocarbon (HC) emissions were observed for 40% blended fuel and were 34.78% and 38.1% reduction, respectively. CO and HC emissions decreased with respect to the engine load. Meanwhile, reverse trends for carbon dioxide (CO2) and nitrogen oxide (NOx) have been observed as 14.57% and 27.85% increases for 100% biodiesel. CO2 and NOx increased with increase in engine load. The mass balance and environmental factor of crude and purified biodiesel were studied to show the environmental suitability of synthesized product. Overall, the results showed that the blended biodiesel can be used as a substitute and has an advantage over diesel fuel. The main contribution derived from this work is to improve engine performance and gaseous emission by using blended biodiesel derived from a recyclable heterogeneous catalyst and waste-cooking-oil feedstock.

Comparing among second, third, and fourth generations (genetically modified) of biodiesel feedstocks from the perspective of engine, exhaust gasses and fatty acid: Comparative assessment

Three new types of biodiesel are examined in this report, including the second, third, and fourth generations. Various factors (oxygen to carbon (O/C), hydrogen to carbon (H/C), carbon-chain lengths (CCLs), saturated and unsaturated fatty acids) have been investigated on engine performance, exhaust gasses, and combustion. Three new types of oil, second (Taxus baccata), third (algae Ulothrix) generation), and fourth (Mentha pulegium) generation (genetically modified) were implemented. The effect of CCLs on viscosity and heating values (HV) proved the promotion of CCLs enhances HV and viscosity; the third generation obtained the highest torque and power compared to the other two generations. Results demonstrated that the advance of the viscosity and diminish of the HV triggers the increase of BSFC and the lowest BSFC presented by the third generation. Regarding outcomes, the rise of unsaturation acids and reduction of CCLs can decline the CN, so the maximum EGT presented by the fourth generation of biodiesel is in contrast with the third generation. The extended CCLs and the lowermost O/C influenced CO and HC, which third-generation showed a minimum. The influence of fatty acids on CN and NOx was displayed, and the third generation gained the lowest NOx. The fourth generation exhibited excessive soot, and the third generation showed the lowest soot. The third-generation biodiesel had the lowest peak pressure compared to other samples. The fourth generation is still less efficient than the third generation, which can be proved that this generation has better results.

Heterogeneous Catalyzed Biodiesel Production Using Cosolvent: A Mini Review

Biodiesel is gaining recognition as a good replacement for typical diesel owing to its renewability, sustainability, and eco-friendly nature. Transesterification is the leading route for biodiesel generation, which occurs during homogeneous/heterogeneous/enzymatic catalysis. Besides this, the usage of heterogeneous catalysts is considered more advantageous over homogeneous catalysts due to the easy catalyst recovery. Consequently, numerous heterogeneous catalysts have been synthesized from multiple sources with the intention of making the manufacturing process more efficient and cost-effective. Alongside this, numerous researchers have attempted to improve the biodiesel yield using heterogeneous catalysts by introducing cosolvents, such that phase limitation between oil and alcohol can be minimized. This short review is aimed at examining the investigations performed to date on heterogeneously catalyzed biodiesel generation in the presence of different cosolvents. It encompasses the techniques for heterogeneous catalyst synthesis, reported in the literature available for heterogeneous catalyzed biodiesel generation using cosolvents and their effects. It also suggests that the application of cosolvent in heterogeneously catalyzed three-phase systems substantially reduces the mass transfer limitation between alcohol and oil phases, which leads to enhancements in biodiesel yield along with reductions in values of optimized parameters, with catalyst weight ranges from 1 to 15 wt. %, and alcohol/oil ratio ranges from 5.5 to 20. The reaction time for getting the maximum conversion ranges from 10 to 600 min in the presence of different cosolvents. Alongside this, most of the time, the biodiesel yield remained above 90% in the presence of cosolvents.

Selectivity of the New Catalyst ZnO-MCM-48-CaO in Esterification of Calophyllum inophyllum Oil

The synthesis of MCM-48 containing surfactants (CTAB and Triton X-100), ZnO, and CaO aimed to find a potential heterogeneous catalyst in the esterification of Calophyllum inophyllum oil to biodiesel. This research is important in the production of biodiesel from vegetable oils with more than 2% free fatty acids (FFA), such as Calophyllum inophyllum oil using heterogeneous catalysts. Synthesis of heterogeneous catalysts, MCM-48 and ZnO-MCM-48-CaO (ZMC), using the hydrothermal method at various calcination temperatures was conducted to find the optimum calcination temperature for the reaction. The activity of the catalyst in the reaction was determined using acid-base titration methods and GC-MS. The MCM-48 catalyst calcined at 650 °C (MCM-48/650) had a catalytic activity of 35.74% and was selective for converting linoleic acid in Calophyllum inophyllum oil to biodiesel. In addition, this catalyst was also capable of cracking the compounds contained in Calophyllum inophyllum oil into suitable hydrocarbons for biodiesel. In the esterification of vegetable oils, four heterogeneous catalysts (MCM-48/550, ZMC/550, ZMC/650, and ZMC/750) had the potential to replace conventional catalysts (H2SO4), particularly in the generation of biodiesel from Calophyllum inophyllum oil.

Generation of biodiesel from edible waste oil using ZIF-67-KOH modified Luffa cylindrica biomass catalyst

To produce biodiesel from edible waste oil, a new heterogeneous catalyst based on Luffa cylindrica biomass was used. For this purpose, first, Luffa cylindrica carbon was modified using zeolite imidazole metal-organic framework (ZIF-67) and KOH and used in the biodiesel production. Fourier-transform infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM), X-ray Powder Diffraction (XRD), Brunauer–Emmett–Teller (BET), Transmission Electron Microscopy (TEM), Raman, and Thermogravimetric Analysis (TGA) techniques were used to investigate the properties of the synthesized catalyst. BET values for activated carbon of Luffa cylindrica (ACL), ZIF-67, ACL/ZIF-67, and ACL/ZIF-67/KOH samples were determined to be 99.714, 1695.7, 956.99, and 2.322 m2/g, respectively, indicating that modification of biomass using ZIF-67 improved its specific active surface, which can retain more KOH in the pores of catalyst. To evaluate the ability of the synthesized catalyst, the effect of various parameters such as reaction time, temperature, amount of catalyst, the molar ratio of oil to methanol, and mixing speed were investigated. The results showed good catalytic activity in converting edible waste oil to biodiesel and maximum efficiency of biodiesel production (98.31%) in laboratory conditions such as a temperature of 65 °C, a catalyst concentration of 3 wt%, a reaction time 3 h, a methanol: oil ratio of 15:1 and a mixing speed of 600 rpm. After determining the optimal laboratory conditions, the study of regeneration and reuse of the catalyst showed that the catalyst had a suitable catalytic activity and can use more than 4 steps in the biodiesel production process. The properties of biodiesel obtained under optimal conditions were evaluated according to the international standards (ASTM D6751 and EN-14214). The results showed that the produced biodiesel possess suitable properties and can replace fuels derived from fossil fuels.

Comparative assessment of waste cooking, chicken waste and waste tire biodiesel blends on performance and emission characteristics

A comparative study and experimental tests were conducted by using second generation biodiesel. Owing to problems being faced in the production of first-generation biodiesel using edible sources, the switch over to another reliable source is much more important. A plenty of research has been going on to mend and produce biodiesel from waste sources. Each experimental tests were conducted in a single cylinder, four stroke diesel engines. The fuels taken for comparison were all derived from non-edible and waste sources such as waste cooking oil, waste chicken fat and waste tire oil. The diesel and blends were mixed in the proportion of 9:1 as 90% diesel and 10% blends. The taken fuel blends were WC10 (Waste cooking oil 10%+ Diesel 90%), WCF10 (Waste Chicken Fat oil 10%+ Diesel 90%) and WT10 (Waste Tire oil 10%+ Diesel 90%). Tests were conducted at four loading conditions with 25% interval as 25%, 50%, 75% and 100%. These biofuel blends results were compared with neat diesel (D100). The performance, emission and combustion qualities were measured. Among the all tried fuels, the better fuel order was D100, WC10, WCF10 and WT10. However, all blended fuels were in the category of oxygenated biofuel derived from not usable products, waste cooking oil biodiesel showed higher Exhaust gas temperature and Bake Power with lower Bake specific fuel consumption than the waste chicken fat and waste tire bio-oil fuels. On comparing the blended fuel excluding the diesel, the WC10, the WT10 proved to be more efficient than WCF10.

MgO@CNT@K2CO3 as a superior catalyst for biodiesel production from waste edible oil using two-step transesterification process

Due to limited fossil fuel resources and greenhouse gas emissions, the use of biodiesel is increasing. In this study, biodiesel was produced from waste edible oil (WEO), as a low-cost oil, using MgO and MgO@CNT@K2CO3 catalysts. The MgO@CNT@K2CO3 catalyst was first synthesized in this study and used to produce biodiesel. To this end, the features of these catalysts were studied using FTIR, BET, XRD, EDX, SEM, and Map analyses. The results indicated that both catalysts have high catalytic activity with mesoporous structures. Due to the high content of free fatty acid (2.43 wt%) in WEO, a two-step transesterification process was used to convert WEO to biodiesel. In the first step, hydrochloric acid homogeneous catalyst was employed to reduce the FFA content and then in the second step, MgO and MgO@CNT@K2CO3 heterogeneous catalysts were used to generate biodiesel. The highest biodiesel yields using MgO and MgO@CNT@K2CO3 were 94.26% and 98.25%, respectively, which were achieved at a catalyst concentration of 4%, temperature of 65 °C, and methanol/oil ratio of 24:1 and 20:1 after 5 and 4 h for MgO and MgO@CNT@K2CO3, respectively. The MgO@CNT@K2CO3 showed the highest biodiesel yield ever achieved from WEO. Also, the physical features of biodiesel were investigated and the results demonstrated that the biodiesel produced are in accordance with ASTM D6751 and EN14214 standards. Moreover, kinetic and thermodynamic studies showed that the transesterification reaction is endothermic and non-spontaneous. Therefore, MgO@CNT@K2CO3 is proposed as a strong and cost-effective catalyst for biodiesel generation from WEO on an industrial scale.

Latest Expansions in Lipid Enhancement of Microalgae for Biodiesel Production: An Update

Research progress on sustainable and renewable biofuel has gained motion over the years, not just due to the rapid reduction of dwindling fossil fuel supplies but also due to environmental and potential energy security issues as well. Intense interest in microalgae (photosynthetic microbes) as a promising feedstock for third-generation biofuels has grown over recent years. Fuels derived from algae are now considered sustainable biofuels that are promising, renewable, and clean. Therefore, selecting the robust species of microalgae with substantial features for quality biodiesel production is the first step in the way of biofuel production. A contemporary investigation is more focused on several strategies and techniques to achieve higher biomass and triglycerides in microalgae. The improvement in lipid enhancement in microalgae species by genetic manipulation approaches, such as metabolic or genetic alteration, and the use of nanotechnology are the most recent ways of improving the production of biomass and lipids. Hence, the current review collects up-to-date approaches for microalgae lipid increase and biodiesel generation. The strategies for high biomass and high lipid yield are discussed. Additionally, various pretreatment procedures that may aid in lipid harvesting efficiency and improve lipid recovery rate are described.

Effect of Reaction Parameters on Catalytic Pyrolysis of Waste Cooking Oil for Production of Sustainable Biodiesel and Biojet by Functionalized Montmorillonite/Chitosan Nanocomposites.

The use of waste oils as pyrolysis feedstocks to manufacture high-grade biofuels has prompted researchers to focus on developing renewable energy to overcome the depletion of fossil fuel supplies and the global warming phenomena. Because of their high hydrogen and volatile matter concentration, waste oils are ideal raw materials for the production of biofuels. It is challenging to attain satisfactory results with conventional methods, such as transesterification, gasification, solvent extraction, and hydrotreating due to flaws such as high energy demand, long time, and high operating costs. Catalytic pyrolysis of waste edible oils was employed as a resource for the generation of biodiesel. The application of the catalytic cracking process has the potential to alleviate the existing situation. In this study of catalytic cracking conversion of waste cooking oil to produce different biofuels, grades were investigated using two heterogeneous catalysts. The catalysts were activated montmorillonite (PAMMT) clay and its modified form using a chitosan biopolymer (PAMMT-CH) nanocomposite. The catalysts were identified using infrared spectroscopy, X-ray diffraction patterns, transmittance electron microscopy images, surface area, and thermal stability. The catalysts were tested for their performances using different amounts (0.1–1% by weight) at a temperature assortment of 200–400 °C during a time range of 60–300 min. The experimental studies were carried out in a batch reactor. GC mass spectra were used to investigate the catalytic cracking products. Fractional distillation is used to separate the final products from various reaction conditions. The physicochemical properties of resulting biofuels were profiled by quantifying their densities, viscosities, specific gravities, pour points, flash and fire points, cetane numbers, carbon and ash residues, and sulfur contents. The optimum conditions of the yield product were 300 and 400 °C, catalyst weights of 0.7 and 0.8% w/v, and reaction times of 120 and 180 min concerning the (PAMMT) and (PAMMT-CH) nanocomposite, respectively. The determined properties were located within the limits of the specific standards of ASTM specifications. As a result, the PAMMT nanocomposite produced biofuel comparable to biodiesel according to ASTM specifications, while the PAMMT-CH nanocomposite produced biofuel comparable to biojet.

Residues to Energy: A Study on Improving the Renewable Energy Mix in Nigeria

The quest for the reduction of global warming which is largely associated with Carbon IV Oxide emission and the reduction of the dependency on fossil fuels for energy generation is a continuous task. Biofuels are coming in to fill the gap with the potential of reduced emissions and being renewable. While biofuels feedstock at times can compete with food cultivation for land and water, some feedstock is just allowed to rot away as wastes and some of such in Nigeria are Mango seeds, African Star Apple seeds, Orange peel and African Pear. This result in environmental pollution and economic loss. The current fraction of renewable energy in Nigeria annual energy production is negligible, and its fraction in the consumed energy is about 3%. This narrative can change with the exploration of her vast agricultural residues. This study seeks to explore some agricultural residues in Nigeria and waste oil, determine their suitability in the generation of energy when converted to biodiesel, and the conversion of biodiesel residue to energy resources. The enormous amount of agricultural residues in Nigeria can be put into use in the generation of biodiesel with comparable favourable characteristics with petroleum diesel and biodiesel wastes also into useful energy sources resulting in a cleaner environment and revenue generation. It is projected that the percentage contribution of renewables to produced energy will be 19% and 47% for her energy consumption.

Structural Design and Research Progress of Heterogeneous Catalysts for the Preparation of Second Generation Biodiesel

Structural Design and Research Progress of Heterogeneous Catalysts for the Preparation of Second Generation Biodiesel

MICROALGAL BIOMASS PRODUCTION AND OIL EXTRACTION FOR SUSTAINABLE BIODIESEL PRODUCTION

Knowing the limitations caused by fossil fuels various researches are being conducted in search of a substitute fuel. One such substitute fuels are biodiesel. A microalgal feedstock is considered as the ideal third generation biodiesel as they are a highly efficient and sustainable source of fuel due to their high accumulation of lipid and are cultured without agricultural land or ecological landscapes, they help withglobal warming and treatment of wastewater. Even though they provide us with all these benefits, they pose various challenges. This review paper focuses on the important aspects of the production of biodiesel and addresses the challenges posed in the process. We discuss the process in detail from the efficient way to select the microalgal strain, effects of biotechnology and genetic engineering in improving the efficiency of the microalgae, the most efficient culture system and bioreactor used, and the optimum conditions that help the accumulation of the most amount of oil, detailed harvesting methods where both the physical, chemical, and biological methods are discussed in detail. The details of oil conversion to biodiesel by transesterification method followed by the recent developments to increase the oil production by the addition of nano-particles, advantages, and prospects have been discussed.

Sustainable biodiesel generation through catalytic transesterification of waste sources: a literature review and bibliometric survey.

Sustainable renewable energy production is being intensely disputed worldwide because fossil fuel resources are declining gradually. One solution is biodiesel production via the transesterification process, which is environmentally feasible due to its low-emission diesel substitute. Significant issues arising with biodiesel production are the cost of the processes, which has stuck its sustainability and the applicability of different resources. In this article, the common biodiesel feedstock such as edible and non-edible vegetable oils, waste oil and animal fats and their advantages and disadvantages were reviewed according to the Web of Science (WOS) database over the timeframe of 1970–2020. The biodiesel feedstock has water or free fatty acid, but it will produce soap by reacting free fatty acids with an alkali catalyst when they present in high portion. This reaction is unfavourable and decreases the biodiesel product yield. This issue can be solved by designing multiple transesterification stages or by employing acidic catalysts to prevent saponification. The second solution is cheaper than the first one and even more applicable because of the abundant source of catalytic materials from a waste product such as rice husk ash, chicken eggshells, fly ash, red mud, steel slag, and coconut shell and lime mud. The overview of the advantages and disadvantages of different homogeneous and heterogeneous catalysts is summarized, and the catalyst promoters and prospects of biodiesel production are also suggested. This research provides beneficial ideas for catalyst synthesis from waste for the transesterification process economically, environmentally and industrially.

Highly Active and Recyclable CoFe2O4/GO/SrO as a Novel Nanocatalyst for Biodiesel Generation From Waste Edible Oil Using Ultrasound Irradiation: Optimization by RSM-CCD Method

Highly Active and Recyclable CoFe2O4/GO/SrO as a Novel Nanocatalyst for Biodiesel Generation From Waste Edible Oil Using Ultrasound Irradiation: Optimization by RSM-CCD Method

Application of waste chalk/CoFe2O4/K2CO3 composite as a reclaimable catalyst for biodiesel generation from sunflower oil

This investigation aimed to produce a new composited catalyst from a waste chalk powder, a waste generated by the construction industry, to produce biodiesel from sunflower oil. The waste chalk was modified by CoFe2O4 nanoparticles and K2CO3. The surface tests showed that the obtained catalyst has been successfully synthesized with desired surface properties. The surface areas of waste chalk, waste chalk/CoFe2O4, and waste chalk/CoFe2O4/K2CO3 were determined 20.8, 77.8, and 5.8 m2/g, respectively. This indicates that the waste chalk/CoFe2O4/K2CO3 catalyst has a lower surface area due to K2CO3 being placed on the catalyst. Results showed the efficiency of RSM-CCD (R2 = 0.992) compared to ANN (R2 = 0.974). It was shown that a contact time of 180 min, a temperature of 65 °C, a waste chalk/CoFe2O4/K2CO3 mass of 2 wt%, and methanol to oil mole ratio of 15:1 gave the highest efficiency (98.87%) of biodiesel production at the laboratory conditions. The kinetic results of the process showed the energy of activation and frequency factor of 11.8 kJ/mol and 0.78 min−1, respectively. Also, the values of ΔH°, ΔS°, and ΔG° at 65 °C was calculated to be 9010.7 J/mol, −256.3 J/mol and 95.7 kJ/mol, respectively, indicating that the biodiesel production process is endothermic requiring high energy for proceeding. The generated catalyst has an efficiency of over 90% up to 6 steps of reuse. The generated biodiesel was met most of the international standard levels.